TI-2019-01312 Aliases CVE-2019-1686 GHSA-9wr9-3p7g-gc32

Cisco ASR 9000 Series Aggregation Services Routers ACL Bypass Vulnerability

MEDIUM 46CWE-284Published 2019-04-17 · Updated 2024-11-19

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Security bypass
Confidentiality · integrity · availability: None · High · None
Fix status: Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-284.

Summary

A vulnerability in the TCP flags inspection feature for access control lists (ACLs) on Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass protection offered by a configured ACL on an affected device. The vulnerability is due to incorrect processing of the ACL applied to an interface of an affected device when Cisco Express Forwarding load balancing using the 3-tuple hash algorithm is enabled. An attacker could exploit this vulnerability by sending traffic through an affected device that should otherwise be denied by the configured ACL. An exploit could allow the attacker to bypass protection offered by a configured ACL on the affected device. There are workarounds that address this vulnerability. Affected Cisco IOS XR versions are: Cisco IOS XR Software Release 5.1.1 and later till first fixed. First Fixed Releases: 6.5.2 and later, 6.6.1 and later.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.01588 75th percentileScored 2026-11-07

Fix Fixed Cisco IOS XR Software (Cisco): 6.5.2, 6.6.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Cisco	Cisco IOS XR Software	before 6.5.2; before 6.6.1	6.5.2, 6.6.1	Patch available	CNA

Cisco IOS XR Software VendorCisco Affected before 6.5.2; before 6.6.1 Fixed in 6.5.2, 6.6.1 Patch available CNA

CPE configurations NVD · 11

CPE	Versions	Role	Vendor
cpe:2.3:o:cisco:ios_xr::::::::	5.1.1 to before 6.5.2; 6.5.3 to before 6.6.1	Vulnerable	Cisco
cpe:2.3:h:cisco:asr_9000v:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:asr_9001:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:asr_9006:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:asr_9010:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:asr_9901:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:asr_9904:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:asr_9906:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:asr_9910:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:asr_9912:-:::::::*	not specified by NVD	Running on	Cisco

cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* Versions 5.1.1 to before 6.5.2; 6.5.3 to before 6.6.1 Vulnerable ·Cisco
cpe:2.3:h:cisco:asr_9000v:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:asr_9001:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:asr_9006:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:asr_9010:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:asr_9901:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:asr_9904:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:asr_9906:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:asr_9910:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:asr_9912:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco

Show 1 more CPE

CPE	Versions	Role	Vendor
cpe:2.3:h:cisco:asr_9922:-:::::::*	not specified by NVD	Running on	Cisco

cpe:2.3:h:cisco:asr_9922:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco

Remediation

Fix · CNA Cisco IOS XR Software (Cisco) Fixed in 6.5.2, 6.6.1

Timeline

2026-10-02 Threatist record created from CVE-2019-1686
2026-10-03 Alias added: GHSA-9wr9-3p7g-gc32

References

Advisory 1

20190417 Cisco ASR 9000 Series Aggregation Services Routers ACL Bypass Vulnerability

TI-2020-02680 Cisco IOS XR Software Cisco Discovery Protocol Format String Vulnerability KEVCVSS 3.1HIGH 8.8
TI-2018-00135 Memory corruption in Cisco IOS, IOS XE, and IOS XR KEVCVSS 3.1HIGH 8.8
TI-2020-03113 Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerabilities KEVCVSS 3.1HIGH 8.6
TI-2020-03110 Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability KEVCVSS 3.1HIGH 8.6
TI-2018-00142 Memory corruption in Cisco IOS, IOS XE, and IOS XR KEVCVSS 3.1HIGH 8.0
TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5

See all 199 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences